/*
 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 2002-2005 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: XPathExpressionImpl.java,v 1.2.4.1 2005/09/10 04:06:55 jeffsuttor Exp $
 */


package com.sun.org.apache.xpath.internal.domapi;

import javax.xml.transform.TransformerException;

import com.sun.org.apache.xpath.internal.XPath;
import com.sun.org.apache.xpath.internal.XPathContext;
import com.sun.org.apache.xpath.internal.objects.XObject;
import com.sun.org.apache.xpath.internal.res.XPATHErrorResources;
import com.sun.org.apache.xpath.internal.res.XPATHMessages;
import org.w3c.dom.DOMException;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.xpath.XPathException;
import org.w3c.dom.xpath.XPathExpression;
import org.w3c.dom.xpath.XPathNamespace;

/**
 * The class provides an implementation of XPathExpression according to the DOM L3 XPath
 * Specification, Working Group Note 26 February 2004.
 *
 * <p>See also the <a href='http://www.w3.org/TR/2004/NOTE-DOM-Level-3-XPath-20040226'>Document
 * Object Model (DOM) Level 3 XPath Specification</a>.</p>
 *
 * <p>The <code>XPathExpression</code> interface represents a parsed and resolved XPath
 * expression.</p>
 *
 * @xsl.usage internal
 * @see org.w3c.dom.xpath.XPathExpression
 */
class XPathExpressionImpl implements XPathExpression {

  /**
   * The xpath object that this expression wraps
   */
  final private XPath m_xpath;

  /**
   * The document to be searched to parallel the case where the XPathEvaluator
   * is obtained by casting a Document.
   */
  final private Document m_doc;

  /**
   * Constructor for XPathExpressionImpl.
   *
   * @param xpath The wrapped XPath object.
   * @param doc The document to be searched, to parallel the case where'' the XPathEvaluator is
   * obtained by casting the document.
   */
  XPathExpressionImpl(XPath xpath, Document doc) {
    m_xpath = xpath;
    m_doc = doc;
  }

  /**
   * This method provides an implementation XPathResult.evaluate according to the DOM L3 XPath
   * Specification, Working Group Note 26 February 2004.
   *
   * <p>See also the <a href='http://www.w3.org/TR/2004/NOTE-DOM-Level-3-XPath-20040226'>Document
   * Object Model (DOM) Level 3 XPath Specification</a>.</p>
   *
   * <p>Evaluates this XPath expression and returns a result.</p>
   *
   * @param contextNode The <code>context</code> is context node for the evaluation of this XPath
   * expression.If the XPathEvaluator was obtained by casting the <code>Document</code> then this
   * must be owned by the same document and must be a <code>Document</code>, <code>Element</code>,
   * <code>Attribute</code>, <code>Text</code>, <code>CDATASection</code>, <code>Comment</code>,
   * <code>ProcessingInstruction</code>, or <code>XPathNamespace</code> node.If the context node is
   * a <code>Text</code> or a <code>CDATASection</code>, then the context is interpreted as the
   * whole logical text node as seen by XPath, unless the node is empty in which case it may not
   * serve as the XPath context.
   * @param type If a specific <code>type</code> is specified, then the result will be coerced to
   * return the specified type relying on XPath conversions and fail if the desired coercion is not
   * possible. This must be one of the type codes of <code>XPathResult</code>.
   * @param result The <code>result</code> specifies a specific result object which may be reused
   * and returned by this method. If this is specified as <code>null</code>or the implementation
   * does not reuse the specified result, a new result object will be constructed and returned.For
   * XPath 1.0 results, this object will be of type <code>XPathResult</code>.
   * @return The result of the evaluation of the XPath expression.For XPath 1.0 results, this object
   * will be of type <code>XPathResult</code>.
   * @throws XPathException TYPE_ERR: Raised if the result cannot be converted to return the
   * specified type.
   * @throws DOMException WRONG_DOCUMENT_ERR: The Node is from a document that is not supported by
   * the XPathEvaluator that created this <code>XPathExpression</code>. <br>NOT_SUPPORTED_ERR: The
   * Node is not a type permitted as an XPath context node.
   * @xsl.usage internal
   * @see org.w3c.dom.xpath.XPathExpression#evaluate(Node, short, XPathResult)
   */
  public Object evaluate(
      Node contextNode,
      short type,
      Object result)
      throws XPathException, DOMException {

    // If the XPathEvaluator was determined by "casting" the document
    if (m_doc != null) {

      // Check that the context node is owned by the same document
      if ((contextNode != m_doc) && (!contextNode.getOwnerDocument().equals(m_doc))) {
        String fmsg = XPATHMessages.createXPATHMessage(XPATHErrorResources.ER_WRONG_DOCUMENT, null);
        throw new DOMException(DOMException.WRONG_DOCUMENT_ERR, fmsg);
      }

      // Check that the context node is an acceptable node type
      short nodeType = contextNode.getNodeType();
      if ((nodeType != Document.DOCUMENT_NODE) &&
          (nodeType != Document.ELEMENT_NODE) &&
          (nodeType != Document.ATTRIBUTE_NODE) &&
          (nodeType != Document.TEXT_NODE) &&
          (nodeType != Document.CDATA_SECTION_NODE) &&
          (nodeType != Document.COMMENT_NODE) &&
          (nodeType != Document.PROCESSING_INSTRUCTION_NODE) &&
          (nodeType != XPathNamespace.XPATH_NAMESPACE_NODE)) {
        String fmsg = XPATHMessages.createXPATHMessage(XPATHErrorResources.ER_WRONG_NODETYPE, null);
        throw new DOMException(DOMException.NOT_SUPPORTED_ERR, fmsg);
      }
    }

    //
    // If the type is not a supported type, throw an exception and be
    // done with it!
    if (!XPathResultImpl.isValidType(type)) {
      String fmsg = XPATHMessages.createXPATHMessage(XPATHErrorResources.ER_INVALID_XPATH_TYPE,
          new Object[]{new Integer(type)});
      throw new XPathException(XPathException.TYPE_ERR, fmsg); // Invalid XPath type argument: {0}
    }

    // Cache xpath context?
    XPathContext xpathSupport = new XPathContext();

    // if m_document is not null, build the DTM from the document
    if (null != m_doc) {
      xpathSupport.getDTMHandleFromNode(m_doc);
    }

    XObject xobj = null;
    try {
      xobj = m_xpath.execute(xpathSupport, contextNode, null);
    } catch (TransformerException te) {
      // What should we do here?
      throw new XPathException(XPathException.INVALID_EXPRESSION_ERR, te.getMessageAndLocation());
    }

    // Create a new XPathResult object
    // Reuse result object passed in?
    // The constructor will check the compatibility of type and xobj and
    // throw an exception if they are not compatible.
    return new XPathResultImpl(type, xobj, contextNode, m_xpath);
  }

}
